The present invention generally relates to environmental control systems (ECSs) and, more particularly, to apparatus and methods of ozone and/or Volatile Organic Compounds (VOC) and/or carbon monoxide conversion in ECSs.
In aircraft, current ECSs receive high pressure air in the form of bleed air from an engine and/or air from an auxiliary power unit (APU). A precooler may receive the bleed air from the engine, while an ozone converter (OC) or combined hydrocarbon and ozone converter (CHOC) or carbon monoxide converter (CMC) may receive both the precooler exhaust with the APU air. From the OC or CHOC or CMC, an air conditioning pack may receive the exhaust flow and send it to the cabin. On more electric aircrafts, the ECS receives air from dedicated Cabin Air Compressors (CAC).
A full bleed ECS for some aircraft has a heat exchanger inlet temperature of ˜200° C. and a normal temperature drop >80° C. Because of the high temperature drop over the heat exchanger, the performance of current catalysts for ozone conversion do not meet the end of life (EOL) requirements. For some hybrid/full electrical aircraft, ECS inlet temperatures are between 30° C.-150° C. With the current OC catalyst, EOL performance can decrease.
Reducing maintenance requirements and increasing EOL performance can produce lower operating costs. Weight reductions that result in fuel savings can also mean lower operating costs and can sometimes be achieved by the elimination of system components.
As can be seen, there is a need for improved apparatus and methods to achieve ozone and/or hydrocarbon and/or carbon monoxide removal from an ECS.